Is there a way to learn to which project or workspace the user is installing the app during the OAuth flow? The documentation says
When an app with App Components is added to a project, the user adding it is sent to the App’s
authenticationUrl.
Are there some additional parameters that are added to the request that would indicate where the app is being installed?
And later on is it possible to query which projects and/or workspaces the app has been installed to via the API?
1000 yes, I need this as well as a developer 
To add to this, we also really need need the project ID to be passed on all calls where there’s a task and workspace ID passed. E.g. get widget metadata and get form metadata.
Since tasks can be multi-homed, there’s no way to know from the task ID which project the widget or form is being requested for and that’s preventing us from enriching the user experience with context.
Regarding Rule Actions, I just want to mention that the action submission (and on-change) request should include the project ID as well. That is, when the action is submitted, you can store metadata about it including the action ID and the project ID. Then when the rule runs, you can pull that metadata and know what project the rule is associated with.